The invention relates generally to the handling of photosensitive materials.
More particularly, the invention relates to a method and arrangement for gripping X-ray film.
A known arrangement for gripping X-ray film in a cassette or camera includes a pair of magnetic units which grip opposite sides of the film. Each of the magnetic units consists of a magnetic sheet and an intensifying screen located on that side of the associated magnetic sheet facing away from the other unit. The dimensions of the magnetic sheets and intensifying screens approximate those of the area of the film to be exposed. At least one of the magnetic sheets is flexible.
The German publication DE-OS 28 02 730.7 discloses a gripping arrangement of the above type in a cassette. A similar gripping arrangement in a camera is described in the German publication DE-OS 29 12 669.0.
It has been found that the use of a magnetic gripping arrangement such as outlined above frequently results in the formation of air bubbles. This causes the intensifying screens and the film to contact one another non-uniformly which adversely affects the quality of the image in that there is a lack of definition. In those cases, as in cameras, where the magnetic units are maintained essentially parallel to one another as they are brought into engagement with the film, it is quite possible for the edges to contact the film before all of the air has escaped from the central region. Air bubbles have also been found in cassettes of the type having a hinged connection between the top and bottom portions thereof, especially large cassettes. The air bubbles in this case stem from the fact that the cassettes are generally closed very rapidly so that the air does not have time to escape completely.